Electronic equipment enclosures are commonly constructed by assembling rigid frame members made of extruded aluminum at mitered corner joints. Typically, the frame members are of a hollow cross section. A corner block comprising two or more extending arms is usually employed to fasten adjacent frame members. The extending connector arms are arranged to be received into the hollowed internal portions of the frame members to provide interlocking engagement between adjacent frame members, thereby preventing lateral separation.
The prior art has heretofore proposed several mitered frame corner constructions employing three-legged connectors. Representative of such prior proposals are the Aschinger U.S. Pat. No. 2,371,493, Humble U.S. Pat. No. 3,144,365 and Suchowski U.S. Pat. No. 3,767,237. In each of these proposals three frame members are joined in a mitered joint with each of the frame members being disposed in perpendicular relationship with respect to the remaining members. The angularly extending arms of the connector are received within formed cavities provided in the adjacent ends of the angularly extending frame members.
Various fastenings including screws and rivets are utilized to securely fasten the connectors within the frame members to firmly hold the frame members in an assembled, mitered relation. Typically, where the frame members are made from extruded aluminum, a force-fitting connector is employed whereby the connector holds the frame member by a friction engagement.
As one of its basic objectives, the present invention seeks to provide an electronic equipment enclosure assembly incorporating a novel and improved mitered frame connection which may be easily and inexpensively constructed in any size from a standard set of components, namely, extruded framing rails, of unique cross section, sheet metal paneling, and two types of novel connector clips. Each of the unique connector clips disclosed herein is constructed from a single piece of sheet metal by a simple stamping and/or bending operation.
Generally, the new electronic equipment enclosure is constructed by assembling extruded aluminum frame rail members as mitered corners to form a parallelpiped skeletal framework. Each frame rail is of a hollow construction and comprises two lateral, longitudinally extending frame walls in right angled relation. The ends of the frame members are mitered at 45.degree. angles so that contiguous frame members may be assembled into a mitered joint in known fashion.
Each of the new and improved frame rails includes a pair of spaced, parallel longitudinally extending inner and outer slots at each lateral edge thereof. The outer slots receive wall panels for closing off the equipment enclosure, while the inner slots receive the corner connector clips and the panel support clips.
Specifically, the inner slots cooperate with a new and improved dish-shaped, corner connector clip to securely fasten contiguous frame members at the mitered corners. The novel connector clip of the present invention comprises three extending arms in mutual perpendicular relation joined at a flat bottom of a dished central portion, which bottom is in a plane disposed at a 45.degree. angle to each of the arms. The connector arms are loosely received in the inner slots of the frame walls for easy assembly. The edges of the connector arms engage the walls of the pairs of inner slots of each of the frame members and thereby tend to secure the frame members from transverse displacement at the mitered joint.
In accordance with the invention, the mid-region of each corner connector clip arm is bent to form a recessed portion. A threaded hole is formed in an inclined surface of the recess and a fastening jackscrew is threadedly received into the hole. After the connector arm is properly positioned in the frame member, the fastening jackscrew may be threaded to engage the frame member in an angled relation, whereby tightening of the fastening screw will also tend to drive the frame member towards the mitered corner and to establish a tight, firm mitered joint with the two adjacent rails.
As another feature of the present invention, a series of panel mounting clips is provided to mount both side walls and shelves to the parallelepiped skeletal frame. Typically, electronic equipment enclosures of the present type require shelves. Due to the great variety of size and shape of the equipment generally enclosed in such enclosures, it is advantageous to provide means to mount shelves in any desired position. Accordingly, each of the panel mounting clips comprises a frame rail engaging arm in right angled relationship to a gusset-like shelf supporting tab. The shelf tab is adapted to project at right angles to the frame rails into the interior equipment positions of the enclosure. The triangular shape allows the tab edges to extend into the plane of the edges of the innermost walls of the frame rails. A pair of winged portions project from the tab and are disposed to lie within the planes of the innermost rail walls. Therefore, the arrangement of the winged portions is such that when the panel mounting clip is inserted into the frame rail, the winged portions form extensions of the innermost lateral walls thereof. Side panels of sheet metal or the like may then be removably or permanently mounted to the equipment enclosure by appropriate fastening means connecting the panels to the winged portions of the mounting clips. The use of winged portions to mount the side panels rather than extended walls of the frame rail extrusions greatly reduces the bulk and weight of the frame rail members that would otehrwise be required, since the winged portions serve as extensions of the frame walls in only those regions where the side panel is intended to be secured to the frame.
The foregoing objects and advantages of the present invention will be further appreciated from a consideration of the following detailed description and accompanying drawings.